Annelida, Mollusca, and Echinodermata

Flashcards covering key concepts from a lecture on Annelida, Mollusca, and Echinodermata phyla.

Class Polychaeta

Bristle worms belonging to the Phylum Annelida, typically marine habitats, characterized by segments, parapodia, and setae; reproduce via separate sexes, external fertilization, and metamorphosis involving a trochophore larva.

Class Oligochaeta

Earthworms belonging to the Phylum Annelida, typically soil habitats, characterized by a clitellum and setae; hermaphroditic, reproduce by aligning and exchanging sperm, the clitellum forms a cocoon, direct development without a larval stage; important for soil aeration and decomposition.

Class Hirudinea

Leeches belonging to the Phylum Annelida, found in freshwater, marine, and terrestrial habitats, characterized by suckers; hermaphroditic, internal fertilization, clitellum make a cocoon, direct development without a larval stage; some are predators, others suck blood. They have a flattened, muscular body.

Phylum Mollusca

Includes snails, slugs, clams, and mussels

Class Gastropoda

Snails and slugs belonging to the Phylum Mollusca, found in land, freshwater, and marine habitats, characterized by a muscular foot, tentacles, radula, and often a shell; reproduce via internal fertilization, some are hermaphrodites, others have separate sexes; life cycle includes a trochophore or veliger larva or direct development for land snails; herbivores or predators.

Class Bivalvia

Clams and mussels belonging to the Phylum Mollusca, generally aquatic habitats, characterized by two shells, gills, adductor muscles, and a foot; reproduce via separate sexes and external fertilization; life cycle includes trochophore and veliger larva; filter feeders.

Class Cephalopoda

Octopus and squid belonging to the Phylum Mollusca, exclusively marine habitats, characterized by tentacles, a beak, a siphon, large eyes, and an ink sac; reproduce via separate sexes and internal fertilization, eggs laid and hatch directly; highly developed brain, eyes, and nervous system; active predators with camouflage abilities.

Phylum Echinodermata

Starfish and urchins, marine benthic habitats, characterized by tube feet, a central disc, radial arms, and a madreporite; reproduce via separate sexes and external fertilization, bipinnaria larva -> settles; capable of regeneration; possess a water vascular system.